Body boards are typically constructed from an expanded closed-cell foam. The body board has a top skin on which riders lay and, a bottom, smooth skin which contacts the wave when riding the body board. A pair of side rails extend between the top skin and bottom skin along a major portion of the perimeter of the body board.
When riding a wave, the object of most riders is to cut across a face of the wave to obtain a long ride and to perform tricks such as spinning the board through 360.degree.. To enable the body board to travel across the face of the wave, a rider must lean to one side of the body board to dig one of the rails into the face of the wave.
In particular wave conditions, or through a riders lack of experience, or rider error, the rail is often not dug into the face of the wave. This can cause the body board and rider to slide down the face of the wave usually causing a "wipeout".
To prevent a body board from sliding down the face of the wave, downwardly extending fins are attached to the bottom skin of the body board. The fins work well in enabling a rider to guide the body board across the face of the wave without slippage of the body board down the face of the wave.
However, the fins often prevent tricks being performed that involve quick rotation of the body board. Further, the fins can cause injury to swimmers or other riders if run over by the body board. Hence, fins that extend downwardly from the bottom skin are undesirable and therefore are not in common use by riders.